Can anyone help me with a broken Adaptec 31605?

T

tojoski

Weaksauce
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Jun 10, 2010
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Hello everyone, after years of lurking I finally have a question worthy of posting.

I picked up a dead Adaptec 31605 off of ebay for $30..after examining it i discovered a couple of the smt chips near the pci-e slot have been broken off..

C450 was easy to identify, it is a capacitor and there is a whole row of them.. about 95nF
R503 on the other hand is a resistor I know, but I have no way to know what it was..

Adaptec support eventually told me that I had a "prototype" card and they didnt have any way to tell me what the values of the components are (no surprise there)

Does anyone have a 31605 around and can test R503 with a multimeter? or atleast take a high-res pic so I can verify that there is in fact supposed to be a resistor there?

I'm pretty confident I can handle soldering those, I've done it a few times before on stuff that small.

I appreciate any help anybody can offer..
 
i have a 31605 that i am replacing in a few days (and a new camera coming on the same order) so i will try and take a few measurements for you

most likely Wednesday
 
Butcher9_9 said:
i have a 31605 that i am replacing in a few days (and a new camera coming on the same order) so i will try and take a few measurements for you

most likely Wednesday
Click to expand...

Awesome, Have you had issues with your card?

dandragonrage said:
you can probably replace the resistor with a light pencil mark ;)
Click to expand...

I considered improvising the resistor, but there's such s huge range in values of the other resistors.. If I can find what it's supposed to be I can rob one out of
my stack of old modems and gfx cards.
 
tojoski said:
C450 was easy to identify, it is a capacitor and there is a whole row of them.. about 95nF
Click to expand...

You probably already know this, but if there are a line of capacitors, then there is a good chance they are attached in parallel. If you use a multimeter to measure the capacitance, it will not equal the capacitance of a single capacitor alone. In order to find the capacitance, you can de-solder the cap and measure it with a multimeter, or use the equation I linked to above to estimate it from the number of caps.

That is, unless, they started to mark the capacitance value on SMD capacitors these days...
 
tojoski said:
Luckily these caps are connected to the pci-e bus, so unless the card is plugged in to something, theres not a complete circuit.
Click to expand...

The presence or lack of a complete circuit doesn't make a difference in this case. In some cases lots of capacitors are used in parallel for some reason (I am not an EE :p). Most notably for the core voltage to the CPU on the motherboard. In that case, you can't just put a multimeter to the cap and measure the capacitance correctly. This puzzled me for a bit when I was replacing caps on a motherboard a while ago. However,

dandragonrage said:
Well, I assume they are on different traces.
Click to expand...

This appears to be correct (I am still not EE, so take this with a grain of salt :cool:). As long as they are on different traces, measuring their capacitance with the multimeter should work fine.
 
well i got my new card so here is what i promised

the R503 resistor seems to be 1 - 1.2ohms but i am not sure if that's the correct

my cheaper multimeter can't make its mind up and it varies depending on where i put the probes , the resistor is only 1mm long so its not that easy (maybe there is a protective coating or tinning stuff that's stopping the measurements from being accurate)

31605503r.jpg
 
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Dude you freakin rock..

I can already tell the folks here on the Hardforum are 1st class..

Now I get to dig through my old modems and video cards and find a resistor..

What kind of compatibility issues have you had with the card?
 
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well the card does not like WD or seagate 1.5tb drives

the wd ones just drop out all the time and the seagate ones come up with an error when you try and create an array (but they work in jbod)

its also not that fast
 
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